The invention relates to residential sprinkler arrangements and, more particularly, to residential sprinkler arrangements satisfying minimum flow rate, pressure and density requirements.
The proposed amendments to the National Fire Protection Association standards NFPA 13D and 13R for residential sprinklers require minimum density of 0.05 gallon per minute per square foot over the area to be protected. In addition, the Underwriters Laboratories revised Standard UL1626 for residential sprinklers requires minimum flow rate of 8, 10, 13, 17 and 20 gallons per minute to protect areas of 144, 196, 256, 324 and 400 square feet, respectively, at a minimum pressure of 7 psi. In order to meet these standards at the lowest required pressure and flow rates, the density distribution of water over the area to be protected by the sprinklers should be substantially uniform.
Various sprinkler arrangements and deflector designs have been proposed heretofore to provide desired water flow rate and distribution patterns at various pressures. For example, the Bosio et al. U.S. Pat. No. 5,687,914 discloses a sprinkler arrangement having a deflector supported from a pair of frame arms which has enlarged tines in the plane of the frame arms with their inner ends bent away from the frame arms and their outer ends inclined slightly toward the frame arms. The Grinnell Model F680 sprinkler has a planar deflector with keyhole-shaped slots distributed around the periphery with the circular part of the keyhole for slots in the plane of the frame arms having a diameter smaller than that of the other slots. Those arrangements, however, do not provide the desired water distribution uniformity for flow rates and pressures of the type mentioned above for residential sprinklers. The Pahila U.S. Pat. No. 6,026,907 discloses one form of residential sprinkler intended to satisfy certain water flow rate and uniformity requirements.
Accordingly, it is an object of the present invention to provide a residential sprinkler arrangement which overcomes disadvantages of the prior art.
Another object of the invention is to provide a residential sprinkler arrangement providing highly uniform water distribution at the minimum required flow rates and pressures for various areas to be protected.
These and other objects of the invention are attained by providing a sprinkler including a sprinkler body with a passage having an outlet opening which is normally closed by a cap retained in position by a thermally responsive element and a deflector spaced from the outlet opening and supported from the sprinkler body by a pair of arms and disposed generally in a plane perpendicular to the axis of the passage, in which the sprinkler has a K factor in the range from about 4 to about 6, preferably about 5, and desirably about 4.9. In addition, the deflector has a central portion and a peripheral portion with a circumferential array of tines in the peripheral portion separated by slot-like openings including a first set of slot-like openings consisting of two slots located in the plane of the frame arms which are longer than the other slot-like openings and a second set of slot-like openings consisting of two slots in the plane perpendicular to the planes of the frame arms which are longer than the remaining slot-like openings.
The deflector preferably includes a third set of slot-like openings consisting of four slots located at about 40xc2x0 to about 50xc2x0, preferably about 45xc2x0, to those planes, a fourth set of slot-like openings includes eight slots which are shorter than all of the other slots and are located at about 11xc2x0 to about 15xc2x0, desirably about 13xc2x0, on each side of each of the plane of the frame arms and the plane perpendicular thereto, and a fifth set of slot-like openings, including eight slots each located between a slot of the fourth set and the adjacent slot of the third set and extending approximately parallel to the slots of the third set.
Preferably the deflector has a planar shape and the first, second, third and fourth sets of slots extend substantially radially inwardly from the perimeter. In a preferred embodiment the deflector has a diameter of about 1.1 to 1.4 inches, preferably about 1.25 inches, and the slots of the first set have a length of about 0.27 to about 0.31 inch, desirably about 0.29 inches and the slots of the second set have a length of about 0.23 to 0.27 inch, desirably about 0.25 inch, while the slots of the third set have a length of about 0.16 to 0.20 inch, desirably about 0.18 inch and the slots of the fourth set have a length of about 0.08 to 0.12 inch, desirably about 0.1 inch.